ipa: raspberrypi: Introduce IpaBase class

Create a new IpaBase class that handles general purpose housekeeping
duties for the Raspberry Pi IPA. The implementation of the new class
is essentially pulled from the existing ipa/rpi/vc4/raspberrypi.cpp file
with a minimal amount of refactoring.

Create a derived IpaVc4 class from IpaBase that handles the VC4 pipeline
specific tasks of the IPA. Again, code for this class implementation is
taken from the existing ipa/rpi/vc4/raspberrypi.cpp with a
minimal amount of refactoring.

The goal of this change is to allow third parties to implement their own
IPA running on the Raspberry Pi without duplicating all of the IPA
housekeeping tasks.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

3 files changed, 1421 insertions, 0 deletions

diff --git a/src/ipa/rpi/common/ipa_base.cpp b/src/ipa/rpi/common/ipa_base.cpp
new file mode 100644
index 00000000..db7a0eb3
--- /dev/null
+++ b/src/ipa/rpi/common/ipa_base.cpp
@@ -0,0 +1,1282 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2019-2023, Raspberry Pi Ltd
+ *
+ * ipa_base.cpp - Raspberry Pi IPA base class
+ */
+
+#include "ipa_base.h"
+
+#include <cmath>
+
+#include <libcamera/base/log.h>
+#include <libcamera/base/span.h>
+#include <libcamera/control_ids.h>
+
+#include "controller/af_algorithm.h"
+#include "controller/af_status.h"
+#include "controller/agc_algorithm.h"
+#include "controller/awb_algorithm.h"
+#include "controller/awb_status.h"
+#include "controller/black_level_status.h"
+#include "controller/ccm_algorithm.h"
+#include "controller/ccm_status.h"
+#include "controller/contrast_algorithm.h"
+#include "controller/denoise_algorithm.h"
+#include "controller/lux_status.h"
+#include "controller/sharpen_algorithm.h"
+#include "controller/statistics.h"
+
+namespace libcamera {
+
+using namespace std::literals::chrono_literals;
+using utils::Duration;
+
+namespace {
+
+/* Number of frame length times to hold in the queue. */
+constexpr unsigned int FrameLengthsQueueSize = 10;
+
+/* Configure the sensor with these values initially. */
+constexpr double defaultAnalogueGain = 1.0;
+constexpr Duration defaultExposureTime = 20.0ms;
+constexpr Duration defaultMinFrameDuration = 1.0s / 30.0;
+constexpr Duration defaultMaxFrameDuration = 250.0s;
+
+/*
+ * Determine the minimum allowable inter-frame duration to run the controller
+ * algorithms. If the pipeline handler provider frames at a rate higher than this,
+ * we rate-limit the controller Prepare() and Process() calls to lower than or
+ * equal to this rate.
+ */
+constexpr Duration controllerMinFrameDuration = 1.0s / 30.0;
+
+/* List of controls handled by the Raspberry Pi IPA */
+const ControlInfoMap::Map ipaControls{
+	{ &controls::AeEnable, ControlInfo(false, true) },
+	{ &controls::ExposureTime, ControlInfo(0, 66666) },
+	{ &controls::AnalogueGain, ControlInfo(1.0f, 16.0f) },
+	{ &controls::AeMeteringMode, ControlInfo(controls::AeMeteringModeValues) },
+	{ &controls::AeConstraintMode, ControlInfo(controls::AeConstraintModeValues) },
+	{ &controls::AeExposureMode, ControlInfo(controls::AeExposureModeValues) },
+	{ &controls::ExposureValue, ControlInfo(-8.0f, 8.0f, 0.0f) },
+	{ &controls::AwbEnable, ControlInfo(false, true) },
+	{ &controls::ColourGains, ControlInfo(0.0f, 32.0f) },
+	{ &controls::AwbMode, ControlInfo(controls::AwbModeValues) },
+	{ &controls::Brightness, ControlInfo(-1.0f, 1.0f, 0.0f) },
+	{ &controls::Contrast, ControlInfo(0.0f, 32.0f, 1.0f) },
+	{ &controls::Saturation, ControlInfo(0.0f, 32.0f, 1.0f) },
+	{ &controls::Sharpness, ControlInfo(0.0f, 16.0f, 1.0f) },
+	{ &controls::ColourCorrectionMatrix, ControlInfo(-16.0f, 16.0f) },
+	{ &controls::ScalerCrop, ControlInfo(Rectangle{}, Rectangle(65535, 65535, 65535, 65535), Rectangle{}) },
+	{ &controls::FrameDurationLimits, ControlInfo(INT64_C(33333), INT64_C(120000)) },
+	{ &controls::draft::NoiseReductionMode, ControlInfo(controls::draft::NoiseReductionModeValues) }
+};
+
+/* IPA controls handled conditionally, if the lens has a focus control */
+const ControlInfoMap::Map ipaAfControls{
+	{ &controls::AfMode, ControlInfo(controls::AfModeValues) },
+	{ &controls::AfRange, ControlInfo(controls::AfRangeValues) },
+	{ &controls::AfSpeed, ControlInfo(controls::AfSpeedValues) },
+	{ &controls::AfMetering, ControlInfo(controls::AfMeteringValues) },
+	{ &controls::AfWindows, ControlInfo(Rectangle{}, Rectangle(65535, 65535, 65535, 65535), Rectangle{}) },
+	{ &controls::AfTrigger, ControlInfo(controls::AfTriggerValues) },
+	{ &controls::AfPause, ControlInfo(controls::AfPauseValues) },
+	{ &controls::LensPosition, ControlInfo(0.0f, 32.0f, 1.0f) }
+};
+
+} /* namespace */
+
+LOG_DEFINE_CATEGORY(IPARPI)
+
+namespace ipa::RPi {
+
+IpaBase::IpaBase()
+	: controller_(), frameCount_(0), mistrustCount_(0), lastRunTimestamp_(0),
+	  firstStart_(true)
+{
+}
+
+IpaBase::~IpaBase()
+{
+}
+
+int32_t IpaBase::init(const IPASettings &settings, const InitParams &params, InitResult *result)
+{
+	/*
+	 * Load the "helper" for this sensor. This tells us all the device specific stuff
+	 * that the kernel driver doesn't. We only do this the first time; we don't need
+	 * to re-parse the metadata after a simple mode-switch for no reason.
+	 */
+	helper_ = std::unique_ptr<RPiController::CamHelper>(RPiController::CamHelper::create(settings.sensorModel));
+	if (!helper_) {
+		LOG(IPARPI, Error) << "Could not create camera helper for "
+				   << settings.sensorModel;
+		return -EINVAL;
+	}
+
+	/*
+	 * Pass out the sensor config to the pipeline handler in order
+	 * to setup the staggered writer class.
+	 */
+	int gainDelay, exposureDelay, vblankDelay, hblankDelay, sensorMetadata;
+	helper_->getDelays(exposureDelay, gainDelay, vblankDelay, hblankDelay);
+	sensorMetadata = helper_->sensorEmbeddedDataPresent();
+
+	result->sensorConfig.gainDelay = gainDelay;
+	result->sensorConfig.exposureDelay = exposureDelay;
+	result->sensorConfig.vblankDelay = vblankDelay;
+	result->sensorConfig.hblankDelay = hblankDelay;
+	result->sensorConfig.sensorMetadata = sensorMetadata;
+
+	/* Load the tuning file for this sensor. */
+	int ret = controller_.read(settings.configurationFile.c_str());
+	if (ret) {
+		LOG(IPARPI, Error)
+			<< "Failed to load tuning data file "
+			<< settings.configurationFile;
+		return ret;
+	}
+
+	lensPresent_ = params.lensPresent;
+
+	controller_.initialise();
+
+	/* Return the controls handled by the IPA */
+	ControlInfoMap::Map ctrlMap = ipaControls;
+	if (lensPresent_)
+		ctrlMap.merge(ControlInfoMap::Map(ipaAfControls));
+	result->controlInfo = ControlInfoMap(std::move(ctrlMap), controls::controls);
+
+	return platformInit(params, result);
+}
+
+int32_t IpaBase::configure(const IPACameraSensorInfo &sensorInfo, const ConfigParams &params,
+			   ConfigResult *result)
+{
+	sensorCtrls_ = params.sensorControls;
+
+	if (!validateSensorControls()) {
+		LOG(IPARPI, Error) << "Sensor control validation failed.";
+		return -1;
+	}
+
+	if (lensPresent_) {
+		lensCtrls_ = params.lensControls;
+		if (!validateLensControls()) {
+			LOG(IPARPI, Warning) << "Lens validation failed, "
+					     << "no lens control will be available.";
+			lensPresent_ = false;
+		}
+	}
+
+	/* Setup a metadata ControlList to output metadata. */
+	libcameraMetadata_ = ControlList(controls::controls);
+
+	/* Re-assemble camera mode using the sensor info. */
+	setMode(sensorInfo);
+
+	mode_.transform = static_cast<libcamera::Transform>(params.transform);
+
+	/* Pass the camera mode to the CamHelper to setup algorithms. */
+	helper_->setCameraMode(mode_);
+
+	/*
+	 * Initialise this ControlList correctly, even if empty, in case the IPA is
+	 * running is isolation mode (passing the ControlList through the IPC layer).
+	 */
+	ControlList ctrls(sensorCtrls_);
+
+	/* The pipeline handler passes out the mode's sensitivity. */
+	result->modeSensitivity = mode_.sensitivity;
+
+	if (firstStart_) {
+		/* Supply initial values for frame durations. */
+		applyFrameDurations(defaultMinFrameDuration, defaultMaxFrameDuration);
+
+		/* Supply initial values for gain and exposure. */
+		AgcStatus agcStatus;
+		agcStatus.shutterTime = defaultExposureTime;
+		agcStatus.analogueGain = defaultAnalogueGain;
+		applyAGC(&agcStatus, ctrls);
+	}
+
+	result->controls = std::move(ctrls);
+
+	/*
+	 * Apply the correct limits to the exposure, gain and frame duration controls
+	 * based on the current sensor mode.
+	 */
+	ControlInfoMap::Map ctrlMap = ipaControls;
+	ctrlMap[&controls::FrameDurationLimits] =
+		ControlInfo(static_cast<int64_t>(mode_.minFrameDuration.get<std::micro>()),
+			    static_cast<int64_t>(mode_.maxFrameDuration.get<std::micro>()));
+
+	ctrlMap[&controls::AnalogueGain] =
+		ControlInfo(static_cast<float>(mode_.minAnalogueGain),
+			    static_cast<float>(mode_.maxAnalogueGain));
+
+	ctrlMap[&controls::ExposureTime] =
+		ControlInfo(static_cast<int32_t>(mode_.minShutter.get<std::micro>()),
+			    static_cast<int32_t>(mode_.maxShutter.get<std::micro>()));
+
+	/* Declare Autofocus controls, only if we have a controllable lens */
+	if (lensPresent_)
+		ctrlMap.merge(ControlInfoMap::Map(ipaAfControls));
+
+	result->controlInfo = ControlInfoMap(std::move(ctrlMap), controls::controls);
+
+	return platformConfigure(params, result);
+}
+
+void IpaBase::start(const ControlList &controls, StartResult *result)
+{
+	RPiController::Metadata metadata;
+
+	if (!controls.empty()) {
+		/* We have been given some controls to action before start. */
+		applyControls(controls);
+	}
+
+	controller_.switchMode(mode_, &metadata);
+
+	/* Reset the frame lengths queue state. */
+	lastTimeout_ = 0s;
+	frameLengths_.clear();
+	frameLengths_.resize(FrameLengthsQueueSize, 0s);
+
+	/* SwitchMode may supply updated exposure/gain values to use. */
+	AgcStatus agcStatus;
+	agcStatus.shutterTime = 0.0s;
+	agcStatus.analogueGain = 0.0;
+
+	metadata.get("agc.status", agcStatus);
+	if (agcStatus.shutterTime && agcStatus.analogueGain) {
+		ControlList ctrls(sensorCtrls_);
+		applyAGC(&agcStatus, ctrls);
+		result->controls = std::move(ctrls);
+		setCameraTimeoutValue();
+	}
+
+	/*
+	 * Initialise frame counts, and decide how many frames must be hidden or
+	 * "mistrusted", which depends on whether this is a startup from cold,
+	 * or merely a mode switch in a running system.
+	 */
+	frameCount_ = 0;
+	if (firstStart_) {
+		dropFrameCount_ = helper_->hideFramesStartup();
+		mistrustCount_ = helper_->mistrustFramesStartup();
+
+		/*
+		 * Query the AGC/AWB for how many frames they may take to
+		 * converge sufficiently. Where these numbers are non-zero
+		 * we must allow for the frames with bad statistics
+		 * (mistrustCount_) that they won't see. But if zero (i.e.
+		 * no convergence necessary), no frames need to be dropped.
+		 */
+		unsigned int agcConvergenceFrames = 0;
+		RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+			controller_.getAlgorithm("agc"));
+		if (agc) {
+			agcConvergenceFrames = agc->getConvergenceFrames();
+			if (agcConvergenceFrames)
+				agcConvergenceFrames += mistrustCount_;
+		}
+
+		unsigned int awbConvergenceFrames = 0;
+		RPiController::AwbAlgorithm *awb = dynamic_cast<RPiController::AwbAlgorithm *>(
+			controller_.getAlgorithm("awb"));
+		if (awb) {
+			awbConvergenceFrames = awb->getConvergenceFrames();
+			if (awbConvergenceFrames)
+				awbConvergenceFrames += mistrustCount_;
+		}
+
+		dropFrameCount_ = std::max({ dropFrameCount_, agcConvergenceFrames, awbConvergenceFrames });
+		LOG(IPARPI, Debug) << "Drop " << dropFrameCount_ << " frames on startup";
+	} else {
+		dropFrameCount_ = helper_->hideFramesModeSwitch();
+		mistrustCount_ = helper_->mistrustFramesModeSwitch();
+	}
+
+	result->dropFrameCount = dropFrameCount_;
+
+	firstStart_ = false;
+	lastRunTimestamp_ = 0;
+}
+
+void IpaBase::mapBuffers(const std::vector<IPABuffer> &buffers)
+{
+	for (const IPABuffer &buffer : buffers) {
+		const FrameBuffer fb(buffer.planes);
+		buffers_.emplace(buffer.id,
+				 MappedFrameBuffer(&fb, MappedFrameBuffer::MapFlag::ReadWrite));
+	}
+}
+
+void IpaBase::unmapBuffers(const std::vector<unsigned int> &ids)
+{
+	for (unsigned int id : ids) {
+		auto it = buffers_.find(id);
+		if (it == buffers_.end())
+			continue;
+
+		buffers_.erase(id);
+	}
+}
+
+void IpaBase::prepareIsp(const PrepareParams &params)
+{
+	applyControls(params.requestControls);
+
+	/*
+	 * At start-up, or after a mode-switch, we may want to
+	 * avoid running the control algos for a few frames in case
+	 * they are "unreliable".
+	 */
+	int64_t frameTimestamp = params.sensorControls.get(controls::SensorTimestamp).value_or(0);
+	unsigned int ipaContext = params.ipaContext % rpiMetadata_.size();
+	RPiController::Metadata &rpiMetadata = rpiMetadata_[ipaContext];
+	Span<uint8_t> embeddedBuffer;
+
+	rpiMetadata.clear();
+	fillDeviceStatus(params.sensorControls, ipaContext);
+
+	if (params.buffers.embedded) {
+		/*
+		 * Pipeline handler has supplied us with an embedded data buffer,
+		 * we must pass it to the CamHelper for parsing.
+		 */
+		auto it = buffers_.find(params.buffers.embedded);
+		ASSERT(it != buffers_.end());
+		embeddedBuffer = it->second.planes()[0];
+	}
+
+	/*
+	 * AGC wants to know the algorithm status from the time it actioned the
+	 * sensor exposure/gain changes. So fetch it from the metadata list
+	 * indexed by the IPA cookie returned, and put it in the current frame
+	 * metadata.
+	 */
+	AgcStatus agcStatus;
+	RPiController::Metadata &delayedMetadata = rpiMetadata_[params.delayContext];
+	if (!delayedMetadata.get<AgcStatus>("agc.status", agcStatus))
+		rpiMetadata.set("agc.delayed_status", agcStatus);
+
+	/*
+	 * This may overwrite the DeviceStatus using values from the sensor
+	 * metadata, and may also do additional custom processing.
+	 */
+	helper_->prepare(embeddedBuffer, rpiMetadata);
+
+	/* Allow a 10% margin on the comparison below. */
+	Duration delta = (frameTimestamp - lastRunTimestamp_) * 1.0ns;
+	if (lastRunTimestamp_ && frameCount_ > dropFrameCount_ &&
+	    delta < controllerMinFrameDuration * 0.9) {
+		/*
+		 * Ensure we merge the previous frame's metadata with the current
+		 * frame. This will not overwrite exposure/gain values for the
+		 * current frame, or any other bits of metadata that were added
+		 * in helper_->Prepare().
+		 */
+		RPiController::Metadata &lastMetadata =
+			rpiMetadata_[(ipaContext ? ipaContext : rpiMetadata_.size()) - 1];
+		rpiMetadata.mergeCopy(lastMetadata);
+		processPending_ = false;
+	} else {
+		processPending_ = true;
+		lastRunTimestamp_ = frameTimestamp;
+	}
+
+	/*
+	 * If a statistics buffer has been passed in, call processStats
+	 * directly now before prepare() since the statistics are available in-line
+	 * with the Bayer frame.
+	 */
+	if (params.buffers.stats)
+		processStats({ params.buffers, params.ipaContext });
+
+	/* Do we need/want to call prepare? */
+	if (processPending_) {
+		controller_.prepare(&rpiMetadata);
+		/* Actually prepare the ISP parameters for the frame. */
+		platformPrepareIsp(params, rpiMetadata);
+	}
+
+	frameCount_++;
+
+	/* Ready to push the input buffer into the ISP. */
+	prepareIspComplete.emit(params.buffers);
+}
+
+void IpaBase::processStats(const ProcessParams &params)
+{
+	unsigned int ipaContext = params.ipaContext % rpiMetadata_.size();
+
+	if (processPending_ && frameCount_ > mistrustCount_) {
+		RPiController::Metadata &rpiMetadata = rpiMetadata_[ipaContext];
+
+		auto it = buffers_.find(params.buffers.stats);
+		if (it == buffers_.end()) {
+			LOG(IPARPI, Error) << "Could not find stats buffer!";
+			return;
+		}
+
+		RPiController::StatisticsPtr statistics = platformProcessStats(it->second.planes()[0]);
+
+		helper_->process(statistics, rpiMetadata);
+		controller_.process(statistics, &rpiMetadata);
+
+		struct AgcStatus agcStatus;
+		if (rpiMetadata.get("agc.status", agcStatus) == 0) {
+			ControlList ctrls(sensorCtrls_);
+			applyAGC(&agcStatus, ctrls);
+			setDelayedControls.emit(ctrls, ipaContext);
+			setCameraTimeoutValue();
+		}
+	}
+
+	reportMetadata(ipaContext);
+	processStatsComplete.emit(params.buffers);
+}
+
+void IpaBase::setMode(const IPACameraSensorInfo &sensorInfo)
+{
+	mode_.bitdepth = sensorInfo.bitsPerPixel;
+	mode_.width = sensorInfo.outputSize.width;
+	mode_.height = sensorInfo.outputSize.height;
+	mode_.sensorWidth = sensorInfo.activeAreaSize.width;
+	mode_.sensorHeight = sensorInfo.activeAreaSize.height;
+	mode_.cropX = sensorInfo.analogCrop.x;
+	mode_.cropY = sensorInfo.analogCrop.y;
+	mode_.pixelRate = sensorInfo.pixelRate;
+
+	/*
+	 * Calculate scaling parameters. The scale_[xy] factors are determined
+	 * by the ratio between the crop rectangle size and the output size.
+	 */
+	mode_.scaleX = sensorInfo.analogCrop.width / sensorInfo.outputSize.width;
+	mode_.scaleY = sensorInfo.analogCrop.height / sensorInfo.outputSize.height;
+
+	/*
+	 * We're not told by the pipeline handler how scaling is split between
+	 * binning and digital scaling. For now, as a heuristic, assume that
+	 * downscaling up to 2 is achieved through binning, and that any
+	 * additional scaling is achieved through digital scaling.
+	 *
+	 * \todo Get the pipeline handle to provide the full data
+	 */
+	mode_.binX = std::min(2, static_cast<int>(mode_.scaleX));
+	mode_.binY = std::min(2, static_cast<int>(mode_.scaleY));
+
+	/* The noise factor is the square root of the total binning factor. */
+	mode_.noiseFactor = std::sqrt(mode_.binX * mode_.binY);
+
+	/*
+	 * Calculate the line length as the ratio between the line length in
+	 * pixels and the pixel rate.
+	 */
+	mode_.minLineLength = sensorInfo.minLineLength * (1.0s / sensorInfo.pixelRate);
+	mode_.maxLineLength = sensorInfo.maxLineLength * (1.0s / sensorInfo.pixelRate);
+
+	/*
+	 * Set the frame length limits for the mode to ensure exposure and
+	 * framerate calculations are clipped appropriately.
+	 */
+	mode_.minFrameLength = sensorInfo.minFrameLength;
+	mode_.maxFrameLength = sensorInfo.maxFrameLength;
+
+	/* Store these for convenience. */
+	mode_.minFrameDuration = mode_.minFrameLength * mode_.minLineLength;
+	mode_.maxFrameDuration = mode_.maxFrameLength * mode_.maxLineLength;
+
+	/*
+	 * Some sensors may have different sensitivities in different modes;
+	 * the CamHelper will know the correct value.
+	 */
+	mode_.sensitivity = helper_->getModeSensitivity(mode_);
+
+	const ControlInfo &gainCtrl = sensorCtrls_.at(V4L2_CID_ANALOGUE_GAIN);
+	const ControlInfo &shutterCtrl = sensorCtrls_.at(V4L2_CID_EXPOSURE);
+
+	mode_.minAnalogueGain = helper_->gain(gainCtrl.min().get<int32_t>());
+	mode_.maxAnalogueGain = helper_->gain(gainCtrl.max().get<int32_t>());
+
+	/* Shutter speed is calculated based on the limits of the frame durations. */
+	mode_.minShutter = helper_->exposure(shutterCtrl.min().get<int32_t>(), mode_.minLineLength);
+	mode_.maxShutter = Duration::max();
+	helper_->getBlanking(mode_.maxShutter,
+			     mode_.minFrameDuration, mode_.maxFrameDuration);
+}
+
+void IpaBase::setCameraTimeoutValue()
+{
+	/*
+	 * Take the maximum value of the exposure queue as the camera timeout
+	 * value to pass back to the pipeline handler. Only signal if it has changed
+	 * from the last set value.
+	 */
+	auto max = std::max_element(frameLengths_.begin(), frameLengths_.end());
+
+	if (*max != lastTimeout_) {
+		setCameraTimeout.emit(max->get<std::milli>());
+		lastTimeout_ = *max;
+	}
+}
+
+bool IpaBase::validateSensorControls()
+{
+	static const uint32_t ctrls[] = {
+		V4L2_CID_ANALOGUE_GAIN,
+		V4L2_CID_EXPOSURE,
+		V4L2_CID_VBLANK,
+		V4L2_CID_HBLANK,
+	};
+
+	for (auto c : ctrls) {
+		if (sensorCtrls_.find(c) == sensorCtrls_.end()) {
+			LOG(IPARPI, Error) << "Unable to find sensor control "
+					   << utils::hex(c);
+			return false;
+		}
+	}
+
+	return true;
+}
+
+bool IpaBase::validateLensControls()
+{
+	if (lensCtrls_.find(V4L2_CID_FOCUS_ABSOLUTE) == lensCtrls_.end()) {
+		LOG(IPARPI, Error) << "Unable to find Lens control V4L2_CID_FOCUS_ABSOLUTE";
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * Converting between enums (used in the libcamera API) and the names that
+ * we use to identify different modes. Unfortunately, the conversion tables
+ * must be kept up-to-date by hand.
+ */
+static const std::map<int32_t, std::string> MeteringModeTable = {
+	{ controls::MeteringCentreWeighted, "centre-weighted" },
+	{ controls::MeteringSpot, "spot" },
+	{ controls::MeteringMatrix, "matrix" },
+	{ controls::MeteringCustom, "custom" },
+};
+
+static const std::map<int32_t, std::string> ConstraintModeTable = {
+	{ controls::ConstraintNormal, "normal" },
+	{ controls::ConstraintHighlight, "highlight" },
+	{ controls::ConstraintShadows, "shadows" },
+	{ controls::ConstraintCustom, "custom" },
+};
+
+static const std::map<int32_t, std::string> ExposureModeTable = {
+	{ controls::ExposureNormal, "normal" },
+	{ controls::ExposureShort, "short" },
+	{ controls::ExposureLong, "long" },
+	{ controls::ExposureCustom, "custom" },
+};
+
+static const std::map<int32_t, std::string> AwbModeTable = {
+	{ controls::AwbAuto, "auto" },
+	{ controls::AwbIncandescent, "incandescent" },
+	{ controls::AwbTungsten, "tungsten" },
+	{ controls::AwbFluorescent, "fluorescent" },
+	{ controls::AwbIndoor, "indoor" },
+	{ controls::AwbDaylight, "daylight" },
+	{ controls::AwbCloudy, "cloudy" },
+	{ controls::AwbCustom, "custom" },
+};
+
+static const std::map<int32_t, RPiController::DenoiseMode> DenoiseModeTable = {
+	{ controls::draft::NoiseReductionModeOff, RPiController::DenoiseMode::Off },
+	{ controls::draft::NoiseReductionModeFast, RPiController::DenoiseMode::ColourFast },
+	{ controls::draft::NoiseReductionModeHighQuality, RPiController::DenoiseMode::ColourHighQuality },
+	{ controls::draft::NoiseReductionModeMinimal, RPiController::DenoiseMode::ColourOff },
+	{ controls::draft::NoiseReductionModeZSL, RPiController::DenoiseMode::ColourHighQuality },
+};
+
+static const std::map<int32_t, RPiController::AfAlgorithm::AfMode> AfModeTable = {
+	{ controls::AfModeManual, RPiController::AfAlgorithm::AfModeManual },
+	{ controls::AfModeAuto, RPiController::AfAlgorithm::AfModeAuto },
+	{ controls::AfModeContinuous, RPiController::AfAlgorithm::AfModeContinuous },
+};
+
+static const std::map<int32_t, RPiController::AfAlgorithm::AfRange> AfRangeTable = {
+	{ controls::AfRangeNormal, RPiController::AfAlgorithm::AfRangeNormal },
+	{ controls::AfRangeMacro, RPiController::AfAlgorithm::AfRangeMacro },
+	{ controls::AfRangeFull, RPiController::AfAlgorithm::AfRangeFull },
+};
+
+static const std::map<int32_t, RPiController::AfAlgorithm::AfPause> AfPauseTable = {
+	{ controls::AfPauseImmediate, RPiController::AfAlgorithm::AfPauseImmediate },
+	{ controls::AfPauseDeferred, RPiController::AfAlgorithm::AfPauseDeferred },
+	{ controls::AfPauseResume, RPiController::AfAlgorithm::AfPauseResume },
+};
+
+void IpaBase::applyControls(const ControlList &controls)
+{
+	using RPiController::AfAlgorithm;
+
+	/* Clear the return metadata buffer. */
+	libcameraMetadata_.clear();
+
+	/* Because some AF controls are mode-specific, handle AF mode change first. */
+	if (controls.contains(controls::AF_MODE)) {
+		AfAlgorithm *af = dynamic_cast<AfAlgorithm *>(controller_.getAlgorithm("af"));
+		if (!af) {
+			LOG(IPARPI, Warning)
+				<< "Could not set AF_MODE - no AF algorithm";
+		}
+
+		int32_t idx = controls.get(controls::AF_MODE).get<int32_t>();
+		auto mode = AfModeTable.find(idx);
+		if (mode == AfModeTable.end()) {
+			LOG(IPARPI, Error) << "AF mode " << idx
+					   << " not recognised";
+		} else if (af)
+			af->setMode(mode->second);
+	}
+
+	/* Iterate over controls */
+	for (auto const &ctrl : controls) {
+		LOG(IPARPI, Debug) << "Request ctrl: "
+				   << controls::controls.at(ctrl.first)->name()
+				   << " = " << ctrl.second.toString();
+
+		switch (ctrl.first) {
+		case controls::AE_ENABLE: {
+			RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+				controller_.getAlgorithm("agc"));
+			if (!agc) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AE_ENABLE - no AGC algorithm";
+				break;
+			}
+
+			if (ctrl.second.get<bool>() == false)
+				agc->disableAuto();
+			else
+				agc->enableAuto();
+
+			libcameraMetadata_.set(controls::AeEnable, ctrl.second.get<bool>());
+			break;
+		}
+
+		case controls::EXPOSURE_TIME: {
+			RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+				controller_.getAlgorithm("agc"));
+			if (!agc) {
+				LOG(IPARPI, Warning)
+					<< "Could not set EXPOSURE_TIME - no AGC algorithm";
+				break;
+			}
+
+			/* The control provides units of microseconds. */
+			agc->setFixedShutter(ctrl.second.get<int32_t>() * 1.0us);
+
+			libcameraMetadata_.set(controls::ExposureTime, ctrl.second.get<int32_t>());
+			break;
+		}
+
+		case controls::ANALOGUE_GAIN: {
+			RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+				controller_.getAlgorithm("agc"));
+			if (!agc) {
+				LOG(IPARPI, Warning)
+					<< "Could not set ANALOGUE_GAIN - no AGC algorithm";
+				break;
+			}
+
+			agc->setFixedAnalogueGain(ctrl.second.get<float>());
+
+			libcameraMetadata_.set(controls::AnalogueGain,
+					       ctrl.second.get<float>());
+			break;
+		}
+
+		case controls::AE_METERING_MODE: {
+			RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+				controller_.getAlgorithm("agc"));
+			if (!agc) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AE_METERING_MODE - no AGC algorithm";
+				break;
+			}
+
+			int32_t idx = ctrl.second.get<int32_t>();
+			if (MeteringModeTable.count(idx)) {
+				agc->setMeteringMode(MeteringModeTable.at(idx));
+				libcameraMetadata_.set(controls::AeMeteringMode, idx);
+			} else {
+				LOG(IPARPI, Error) << "Metering mode " << idx
+						   << " not recognised";
+			}
+			break;
+		}
+
+		case controls::AE_CONSTRAINT_MODE: {
+			RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+				controller_.getAlgorithm("agc"));
+			if (!agc) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AE_CONSTRAINT_MODE - no AGC algorithm";
+				break;
+			}
+
+			int32_t idx = ctrl.second.get<int32_t>();
+			if (ConstraintModeTable.count(idx)) {
+				agc->setConstraintMode(ConstraintModeTable.at(idx));
+				libcameraMetadata_.set(controls::AeConstraintMode, idx);
+			} else {
+				LOG(IPARPI, Error) << "Constraint mode " << idx
+						   << " not recognised";
+			}
+			break;
+		}
+
+		case controls::AE_EXPOSURE_MODE: {
+			RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+				controller_.getAlgorithm("agc"));
+			if (!agc) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AE_EXPOSURE_MODE - no AGC algorithm";
+				break;
+			}
+
+			int32_t idx = ctrl.second.get<int32_t>();
+			if (ExposureModeTable.count(idx)) {
+				agc->setExposureMode(ExposureModeTable.at(idx));
+				libcameraMetadata_.set(controls::AeExposureMode, idx);
+			} else {
+				LOG(IPARPI, Error) << "Exposure mode " << idx
+						   << " not recognised";
+			}
+			break;
+		}
+
+		case controls::EXPOSURE_VALUE: {
+			RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+				controller_.getAlgorithm("agc"));
+			if (!agc) {
+				LOG(IPARPI, Warning)
+					<< "Could not set EXPOSURE_VALUE - no AGC algorithm";
+				break;
+			}
+
+			/*
+			 * The SetEv() function takes in a direct exposure multiplier.
+			 * So convert to 2^EV
+			 */
+			double ev = pow(2.0, ctrl.second.get<float>());
+			agc->setEv(ev);
+			libcameraMetadata_.set(controls::ExposureValue,
+					       ctrl.second.get<float>());
+			break;
+		}
+
+		case controls::AWB_ENABLE: {
+			RPiController::AwbAlgorithm *awb = dynamic_cast<RPiController::AwbAlgorithm *>(
+				controller_.getAlgorithm("awb"));
+			if (!awb) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AWB_ENABLE - no AWB algorithm";
+				break;
+			}
+
+			if (ctrl.second.get<bool>() == false)
+				awb->disableAuto();
+			else
+				awb->enableAuto();
+
+			libcameraMetadata_.set(controls::AwbEnable,
+					       ctrl.second.get<bool>());
+			break;
+		}
+
+		case controls::AWB_MODE: {
+			RPiController::AwbAlgorithm *awb = dynamic_cast<RPiController::AwbAlgorithm *>(
+				controller_.getAlgorithm("awb"));
+			if (!awb) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AWB_MODE - no AWB algorithm";
+				break;
+			}
+
+			int32_t idx = ctrl.second.get<int32_t>();
+			if (AwbModeTable.count(idx)) {
+				awb->setMode(AwbModeTable.at(idx));
+				libcameraMetadata_.set(controls::AwbMode, idx);
+			} else {
+				LOG(IPARPI, Error) << "AWB mode " << idx
+						   << " not recognised";
+			}
+			break;
+		}
+
+		case controls::COLOUR_GAINS: {
+			auto gains = ctrl.second.get<Span<const float>>();
+			RPiController::AwbAlgorithm *awb = dynamic_cast<RPiController::AwbAlgorithm *>(
+				controller_.getAlgorithm("awb"));
+			if (!awb) {
+				LOG(IPARPI, Warning)
+					<< "Could not set COLOUR_GAINS - no AWB algorithm";
+				break;
+			}
+
+			awb->setManualGains(gains[0], gains[1]);
+			if (gains[0] != 0.0f && gains[1] != 0.0f)
+				/* A gain of 0.0f will switch back to auto mode. */
+				libcameraMetadata_.set(controls::ColourGains,
+						       { gains[0], gains[1] });
+			break;
+		}
+
+		case controls::BRIGHTNESS: {
+			RPiController::ContrastAlgorithm *contrast = dynamic_cast<RPiController::ContrastAlgorithm *>(
+				controller_.getAlgorithm("contrast"));
+			if (!contrast) {
+				LOG(IPARPI, Warning)
+					<< "Could not set BRIGHTNESS - no contrast algorithm";
+				break;
+			}
+
+			contrast->setBrightness(ctrl.second.get<float>() * 65536);
+			libcameraMetadata_.set(controls::Brightness,
+					       ctrl.second.get<float>());
+			break;
+		}
+
+		case controls::CONTRAST: {
+			RPiController::ContrastAlgorithm *contrast = dynamic_cast<RPiController::ContrastAlgorithm *>(
+				controller_.getAlgorithm("contrast"));
+			if (!contrast) {
+				LOG(IPARPI, Warning)
+					<< "Could not set CONTRAST - no contrast algorithm";
+				break;
+			}
+
+			contrast->setContrast(ctrl.second.get<float>());
+			libcameraMetadata_.set(controls::Contrast,
+					       ctrl.second.get<float>());
+			break;
+		}
+
+		case controls::SATURATION: {
+			RPiController::CcmAlgorithm *ccm = dynamic_cast<RPiController::CcmAlgorithm *>(
+				controller_.getAlgorithm("ccm"));
+			if (!ccm) {
+				LOG(IPARPI, Warning)
+					<< "Could not set SATURATION - no ccm algorithm";
+				break;
+			}
+
+			ccm->setSaturation(ctrl.second.get<float>());
+			libcameraMetadata_.set(controls::Saturation,
+					       ctrl.second.get<float>());
+			break;
+		}
+
+		case controls::SHARPNESS: {
+			RPiController::SharpenAlgorithm *sharpen = dynamic_cast<RPiController::SharpenAlgorithm *>(
+				controller_.getAlgorithm("sharpen"));
+			if (!sharpen) {
+				LOG(IPARPI, Warning)
+					<< "Could not set SHARPNESS - no sharpen algorithm";
+				break;
+			}
+
+			sharpen->setStrength(ctrl.second.get<float>());
+			libcameraMetadata_.set(controls::Sharpness,
+					       ctrl.second.get<float>());
+			break;
+		}
+
+		case controls::SCALER_CROP: {
+			/* We do nothing with this, but should avoid the warning below. */
+			break;
+		}
+
+		case controls::FRAME_DURATION_LIMITS: {
+			auto frameDurations = ctrl.second.get<Span<const int64_t>>();
+			applyFrameDurations(frameDurations[0] * 1.0us, frameDurations[1] * 1.0us);
+			break;
+		}
+
+		case controls::NOISE_REDUCTION_MODE: {
+			RPiController::DenoiseAlgorithm *sdn = dynamic_cast<RPiController::DenoiseAlgorithm *>(
+				controller_.getAlgorithm("SDN"));
+			/* Some platforms may have a combined "denoise" algorithm instead. */
+			if (!sdn)
+				sdn = dynamic_cast<RPiController::DenoiseAlgorithm *>(
+				controller_.getAlgorithm("denoise"));
+			if (!sdn) {
+				LOG(IPARPI, Warning)
+					<< "Could not set NOISE_REDUCTION_MODE - no SDN algorithm";
+				break;
+			}
+
+			int32_t idx = ctrl.second.get<int32_t>();
+			auto mode = DenoiseModeTable.find(idx);
+			if (mode != DenoiseModeTable.end()) {
+				sdn->setMode(mode->second);
+
+				/*
+				 * \todo If the colour denoise is not going to run due to an
+				 * analysis image resolution or format mismatch, we should
+				 * report the status correctly in the metadata.
+				 */
+				libcameraMetadata_.set(controls::draft::NoiseReductionMode, idx);
+			} else {
+				LOG(IPARPI, Error) << "Noise reduction mode " << idx
+						   << " not recognised";
+			}
+			break;
+		}
+
+		case controls::AF_MODE:
+			break; /* We already handled this one above */
+
+		case controls::AF_RANGE: {
+			AfAlgorithm *af = dynamic_cast<AfAlgorithm *>(controller_.getAlgorithm("af"));
+			if (!af) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AF_RANGE - no focus algorithm";
+				break;
+			}
+
+			auto range = AfRangeTable.find(ctrl.second.get<int32_t>());
+			if (range == AfRangeTable.end()) {
+				LOG(IPARPI, Error) << "AF range " << ctrl.second.get<int32_t>()
+						   << " not recognised";
+				break;
+			}
+			af->setRange(range->second);
+			break;
+		}
+
+		case controls::AF_SPEED: {
+			AfAlgorithm *af = dynamic_cast<AfAlgorithm *>(controller_.getAlgorithm("af"));
+			if (!af) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AF_SPEED - no focus algorithm";
+				break;
+			}
+
+			AfAlgorithm::AfSpeed speed = ctrl.second.get<int32_t>() == controls::AfSpeedFast ?
+						      AfAlgorithm::AfSpeedFast : AfAlgorithm::AfSpeedNormal;
+			af->setSpeed(speed);
+			break;
+		}
+
+		case controls::AF_METERING: {
+			AfAlgorithm *af = dynamic_cast<AfAlgorithm *>(controller_.getAlgorithm("af"));
+			if (!af) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AF_METERING - no AF algorithm";
+				break;
+			}
+			af->setMetering(ctrl.second.get<int32_t>() == controls::AfMeteringWindows);
+			break;
+		}
+
+		case controls::AF_WINDOWS: {
+			AfAlgorithm *af = dynamic_cast<AfAlgorithm *>(controller_.getAlgorithm("af"));
+			if (!af) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AF_WINDOWS - no AF algorithm";
+				break;
+			}
+			af->setWindows(ctrl.second.get<Span<const Rectangle>>());
+			break;
+		}
+
+		case controls::AF_PAUSE: {
+			AfAlgorithm *af = dynamic_cast<AfAlgorithm *>(controller_.getAlgorithm("af"));
+			if (!af || af->getMode() != AfAlgorithm::AfModeContinuous) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AF_PAUSE - no AF algorithm or not Continuous";
+				break;
+			}
+			auto pause = AfPauseTable.find(ctrl.second.get<int32_t>());
+			if (pause == AfPauseTable.end()) {
+				LOG(IPARPI, Error) << "AF pause " << ctrl.second.get<int32_t>()
+						   << " not recognised";
+				break;
+			}
+			af->pause(pause->second);
+			break;
+		}
+
+		case controls::AF_TRIGGER: {
+			AfAlgorithm *af = dynamic_cast<AfAlgorithm *>(controller_.getAlgorithm("af"));
+			if (!af || af->getMode() != AfAlgorithm::AfModeAuto) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AF_TRIGGER - no AF algorithm or not Auto";
+				break;
+			} else {
+				if (ctrl.second.get<int32_t>() == controls::AfTriggerStart)
+					af->triggerScan();
+				else
+					af->cancelScan();
+			}
+			break;
+		}
+
+		case controls::LENS_POSITION: {
+			AfAlgorithm *af = dynamic_cast<AfAlgorithm *>(controller_.getAlgorithm("af"));
+			if (af) {
+				int32_t hwpos;
+				if (af->setLensPosition(ctrl.second.get<float>(), &hwpos)) {
+					ControlList lensCtrls(lensCtrls_);
+					lensCtrls.set(V4L2_CID_FOCUS_ABSOLUTE, hwpos);
+					setLensControls.emit(lensCtrls);
+				}
+			} else {
+				LOG(IPARPI, Warning)
+					<< "Could not set LENS_POSITION - no AF algorithm";
+			}
+			break;
+		}
+
+		default:
+			LOG(IPARPI, Warning)
+				<< "Ctrl " << controls::controls.at(ctrl.first)->name()
+				<< " is not handled.";
+			break;
+		}
+	}
+
+	/* Give derived classes a chance to examine the new controls. */
+	handleControls(controls);
+}
+
+void IpaBase::fillDeviceStatus(const ControlList &sensorControls, unsigned int ipaContext)
+{
+	DeviceStatus deviceStatus = {};
+
+	int32_t exposureLines = sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
+	int32_t gainCode = sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>();
+	int32_t vblank = sensorControls.get(V4L2_CID_VBLANK).get<int32_t>();
+	int32_t hblank = sensorControls.get(V4L2_CID_HBLANK).get<int32_t>();
+
+	deviceStatus.lineLength = helper_->hblankToLineLength(hblank);
+	deviceStatus.shutterSpeed = helper_->exposure(exposureLines, deviceStatus.lineLength);
+	deviceStatus.analogueGain = helper_->gain(gainCode);
+	deviceStatus.frameLength = mode_.height + vblank;
+
+	RPiController::AfAlgorithm *af = dynamic_cast<RPiController::AfAlgorithm *>(
+			controller_.getAlgorithm("af"));
+	if (af)
+		deviceStatus.lensPosition = af->getLensPosition();
+
+	LOG(IPARPI, Debug) << "Metadata - " << deviceStatus;
+
+	rpiMetadata_[ipaContext].set("device.status", deviceStatus);
+}
+
+void IpaBase::reportMetadata(unsigned int ipaContext)
+{
+	RPiController::Metadata &rpiMetadata = rpiMetadata_[ipaContext];
+	std::unique_lock<RPiController::Metadata> lock(rpiMetadata);
+
+	/*
+	 * Certain information about the current frame and how it will be
+	 * processed can be extracted and placed into the libcamera metadata
+	 * buffer, where an application could query it.
+	 */
+	DeviceStatus *deviceStatus = rpiMetadata.getLocked<DeviceStatus>("device.status");
+	if (deviceStatus) {
+		libcameraMetadata_.set(controls::ExposureTime,
+				       deviceStatus->shutterSpeed.get<std::micro>());
+		libcameraMetadata_.set(controls::AnalogueGain, deviceStatus->analogueGain);
+		libcameraMetadata_.set(controls::FrameDuration,
+				       helper_->exposure(deviceStatus->frameLength, deviceStatus->lineLength).get<std::micro>());
+		if (deviceStatus->sensorTemperature)
+			libcameraMetadata_.set(controls::SensorTemperature, *deviceStatus->sensorTemperature);
+		if (deviceStatus->lensPosition)
+			libcameraMetadata_.set(controls::LensPosition, *deviceStatus->lensPosition);
+	}
+
+	AgcStatus *agcStatus = rpiMetadata.getLocked<AgcStatus>("agc.status");
+	if (agcStatus) {
+		libcameraMetadata_.set(controls::AeLocked, agcStatus->locked);
+		libcameraMetadata_.set(controls::DigitalGain, agcStatus->digitalGain);
+	}
+
+	LuxStatus *luxStatus = rpiMetadata.getLocked<LuxStatus>("lux.status");
+	if (luxStatus)
+		libcameraMetadata_.set(controls::Lux, luxStatus->lux);
+
+	AwbStatus *awbStatus = rpiMetadata.getLocked<AwbStatus>("awb.status");
+	if (awbStatus) {
+		libcameraMetadata_.set(controls::ColourGains, { static_cast<float>(awbStatus->gainR),
+								static_cast<float>(awbStatus->gainB) });
+		libcameraMetadata_.set(controls::ColourTemperature, awbStatus->temperatureK);
+	}
+
+	BlackLevelStatus *blackLevelStatus = rpiMetadata.getLocked<BlackLevelStatus>("black_level.status");
+	if (blackLevelStatus)
+		libcameraMetadata_.set(controls::SensorBlackLevels,
+				       { static_cast<int32_t>(blackLevelStatus->blackLevelR),
+					 static_cast<int32_t>(blackLevelStatus->blackLevelG),
+					 static_cast<int32_t>(blackLevelStatus->blackLevelG),
+					 static_cast<int32_t>(blackLevelStatus->blackLevelB) });
+
+	RPiController::FocusRegions *focusStatus =
+		rpiMetadata.getLocked<RPiController::FocusRegions>("focus.status");
+	if (focusStatus) {
+		/*
+		 * Calculate the average FoM over the central (symmetric) positions
+		 * to give an overall scene FoM. This can change later if it is
+		 * not deemed suitable.
+		 */
+		libcamera::Size size = focusStatus->size();
+		unsigned rows = size.height;
+		unsigned cols = size.width;
+
+		uint64_t sum = 0;
+		unsigned int numRegions = 0;
+		for (unsigned r = rows / 3; r < rows - rows / 3; ++r) {
+			for (unsigned c = cols / 4; c < cols - cols / 4; ++c) {
+				sum += focusStatus->get({ (int)c, (int)r }).val;
+				numRegions++;
+			}
+		}
+
+		uint32_t focusFoM = (sum / numRegions) >> 16;
+		libcameraMetadata_.set(controls::FocusFoM, focusFoM);
+	}
+
+	CcmStatus *ccmStatus = rpiMetadata.getLocked<CcmStatus>("ccm.status");
+	if (ccmStatus) {
+		float m[9];
+		for (unsigned int i = 0; i < 9; i++)
+			m[i] = ccmStatus->matrix[i];
+		libcameraMetadata_.set(controls::ColourCorrectionMatrix, m);
+	}
+
+	const AfStatus *afStatus = rpiMetadata.getLocked<AfStatus>("af.status");
+	if (afStatus) {
+		int32_t s, p;
+		switch (afStatus->state) {
+		case AfState::Scanning:
+			s = controls::AfStateScanning;
+			break;
+		case AfState::Focused:
+			s = controls::AfStateFocused;
+			break;
+		case AfState::Failed:
+			s = controls::AfStateFailed;
+			break;
+		default:
+			s = controls::AfStateIdle;
+		}
+		switch (afStatus->pauseState) {
+		case AfPauseState::Pausing:
+			p = controls::AfPauseStatePausing;
+			break;
+		case AfPauseState::Paused:
+			p = controls::AfPauseStatePaused;
+			break;
+		default:
+			p = controls::AfPauseStateRunning;
+		}
+		libcameraMetadata_.set(controls::AfState, s);
+		libcameraMetadata_.set(controls::AfPauseState, p);
+	}
+
+	metadataReady.emit(libcameraMetadata_);
+}
+
+void IpaBase::applyFrameDurations(Duration minFrameDuration, Duration maxFrameDuration)
+{
+	/*
+	 * This will only be applied once AGC recalculations occur.
+	 * The values may be clamped based on the sensor mode capabilities as well.
+	 */
+	minFrameDuration_ = minFrameDuration ? minFrameDuration : defaultMinFrameDuration;
+	maxFrameDuration_ = maxFrameDuration ? maxFrameDuration : defaultMaxFrameDuration;
+	minFrameDuration_ = std::clamp(minFrameDuration_,
+				       mode_.minFrameDuration, mode_.maxFrameDuration);
+	maxFrameDuration_ = std::clamp(maxFrameDuration_,
+				       mode_.minFrameDuration, mode_.maxFrameDuration);
+	maxFrameDuration_ = std::max(maxFrameDuration_, minFrameDuration_);
+
+	/* Return the validated limits via metadata. */
+	libcameraMetadata_.set(controls::FrameDurationLimits,
+			       { static_cast<int64_t>(minFrameDuration_.get<std::micro>()),
+				 static_cast<int64_t>(maxFrameDuration_.get<std::micro>()) });
+
+	/*
+	 * Calculate the maximum exposure time possible for the AGC to use.
+	 * getBlanking() will update maxShutter with the largest exposure
+	 * value possible.
+	 */
+	Duration maxShutter = Duration::max();
+	helper_->getBlanking(maxShutter, minFrameDuration_, maxFrameDuration_);
+
+	RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+		controller_.getAlgorithm("agc"));
+	agc->setMaxShutter(maxShutter);
+}
+
+void IpaBase::applyAGC(const struct AgcStatus *agcStatus, ControlList &ctrls)
+{
+	const int32_t minGainCode = helper_->gainCode(mode_.minAnalogueGain);
+	const int32_t maxGainCode = helper_->gainCode(mode_.maxAnalogueGain);
+	int32_t gainCode = helper_->gainCode(agcStatus->analogueGain);
+
+	/*
+	 * Ensure anything larger than the max gain code will not be passed to
+	 * DelayedControls. The AGC will correctly handle a lower gain returned
+	 * by the sensor, provided it knows the actual gain used.
+	 */
+	gainCode = std::clamp<int32_t>(gainCode, minGainCode, maxGainCode);
+
+	/* getBlanking might clip exposure time to the fps limits. */
+	Duration exposure = agcStatus->shutterTime;
+	auto [vblank, hblank] = helper_->getBlanking(exposure, minFrameDuration_, maxFrameDuration_);
+	int32_t exposureLines = helper_->exposureLines(exposure,
+						       helper_->hblankToLineLength(hblank));
+
+	LOG(IPARPI, Debug) << "Applying AGC Exposure: " << exposure
+			   << " (Shutter lines: " << exposureLines << ", AGC requested "
+			   << agcStatus->shutterTime << ") Gain: "
+			   << agcStatus->analogueGain << " (Gain Code: "
+			   << gainCode << ")";
+
+	ctrls.set(V4L2_CID_VBLANK, static_cast<int32_t>(vblank));
+	ctrls.set(V4L2_CID_EXPOSURE, exposureLines);
+	ctrls.set(V4L2_CID_ANALOGUE_GAIN, gainCode);
+
+	/*
+	 * At present, there is no way of knowing if a control is read-only.
+	 * As a workaround, assume that if the minimum and maximum values of
+	 * the V4L2_CID_HBLANK control are the same, it implies the control
+	 * is read-only. This seems to be the case for all the cameras our IPA
+	 * works with.
+	 *
+	 * \todo The control API ought to have a flag to specify if a control
+	 * is read-only which could be used below.
+	 */
+	if (mode_.minLineLength != mode_.maxLineLength)
+		ctrls.set(V4L2_CID_HBLANK, static_cast<int32_t>(hblank));
+
+	/*
+	 * Store the frame length times in a circular queue, up-to FrameLengthsQueueSize
+	 * elements. This will be used to advertise a camera timeout value to the
+	 * pipeline handler.
+	 */
+	frameLengths_.pop_front();
+	frameLengths_.push_back(helper_->exposure(vblank + mode_.height,
+						  helper_->hblankToLineLength(hblank)));
+}
+
+} /* namespace ipa::RPi */
+
+} /* namespace libcamera */
diff --git a/src/ipa/rpi/common/ipa_base.h b/src/ipa/rpi/common/ipa_base.h
new file mode 100644
index 00000000..6f9c46bb
--- /dev/null
+++ b/src/ipa/rpi/common/ipa_base.h
@@ -0,0 +1,122 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2023, Raspberry Pi Ltd
+ *
+ * ipa_base.h - Raspberry Pi IPA base class
+ */
+#pragma once
+
+#include <array>
+#include <deque>
+#include <map>
+#include <stdint.h>
+
+#include <libcamera/base/utils.h>
+#include <libcamera/controls.h>
+
+#include <libcamera/ipa/raspberrypi_ipa_interface.h>
+
+#include "libcamera/internal/mapped_framebuffer.h"
+
+#include "cam_helper/cam_helper.h"
+#include "controller/agc_status.h"
+#include "controller/camera_mode.h"
+#include "controller/controller.h"
+#include "controller/metadata.h"
+
+namespace libcamera {
+
+namespace ipa::RPi {
+
+class IpaBase : public IPARPiInterface
+{
+public:
+	IpaBase();
+	~IpaBase();
+
+	int32_t init(const IPASettings &settings, const InitParams &params, InitResult *result) override;
+	int32_t configure(const IPACameraSensorInfo &sensorInfo, const ConfigParams &params,
+			  ConfigResult *result) override;
+
+	void start(const ControlList &controls, StartResult *result) override;
+	void stop() override {}
+
+	void mapBuffers(const std::vector<IPABuffer> &buffers) override;
+	void unmapBuffers(const std::vector<unsigned int> &ids) override;
+
+	void prepareIsp(const PrepareParams &params) override;
+	void processStats(const ProcessParams &params) override;
+
+protected:
+	/* Raspberry Pi controller specific defines. */
+	std::unique_ptr<RPiController::CamHelper> helper_;
+	RPiController::Controller controller_;
+
+	ControlInfoMap sensorCtrls_;
+	ControlInfoMap lensCtrls_;
+
+	/* Camera sensor params. */
+	CameraMode mode_;
+
+	/* Track the frame length times over FrameLengthsQueueSize frames. */
+	std::deque<utils::Duration> frameLengths_;
+	utils::Duration lastTimeout_;
+
+private:
+	/* Number of metadata objects available in the context list. */
+	static constexpr unsigned int numMetadataContexts = 16;
+
+	virtual int32_t platformInit(const InitParams &params, InitResult *result) = 0;
+	virtual int32_t platformConfigure(const ConfigParams &params, ConfigResult *result) = 0;
+
+	virtual void platformPrepareIsp(const PrepareParams &params,
+					RPiController::Metadata &rpiMetadata) = 0;
+	virtual RPiController::StatisticsPtr platformProcessStats(Span<uint8_t> mem) = 0;
+
+	void setMode(const IPACameraSensorInfo &sensorInfo);
+	void setCameraTimeoutValue();
+	bool validateSensorControls();
+	bool validateLensControls();
+	void applyControls(const ControlList &controls);
+	virtual void handleControls(const ControlList &controls) = 0;
+	void fillDeviceStatus(const ControlList &sensorControls, unsigned int ipaContext);
+	void reportMetadata(unsigned int ipaContext);
+	void applyFrameDurations(utils::Duration minFrameDuration, utils::Duration maxFrameDuration);
+	void applyAGC(const struct AgcStatus *agcStatus, ControlList &ctrls);
+
+	std::map<unsigned int, MappedFrameBuffer> buffers_;
+
+	bool lensPresent_;
+	ControlList libcameraMetadata_;
+
+	std::array<RPiController::Metadata, numMetadataContexts> rpiMetadata_;
+
+	/*
+	 * We count frames to decide if the frame must be hidden (e.g. from
+	 * display) or mistrusted (i.e. not given to the control algos).
+	 */
+	uint64_t frameCount_;
+
+	/* How many frames we should avoid running control algos on. */
+	unsigned int mistrustCount_;
+
+	/* Number of frames that need to be dropped on startup. */
+	unsigned int dropFrameCount_;
+
+	/* Frame timestamp for the last run of the controller. */
+	uint64_t lastRunTimestamp_;
+
+	/* Do we run a Controller::process() for this frame? */
+	bool processPending_;
+
+	/* Distinguish the first camera start from others. */
+	bool firstStart_;
+
+	/* Frame duration (1/fps) limits. */
+	utils::Duration minFrameDuration_;
+	utils::Duration maxFrameDuration_;
+};
+
+} /* namespace ipa::RPi */
+
+} /* namespace libcamera */
diff --git a/src/ipa/rpi/common/meson.build b/src/ipa/rpi/common/meson.build
new file mode 100644
index 00000000..73d2ee73
--- /dev/null
+++ b/src/ipa/rpi/common/meson.build
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: CC0-1.0
+
+rpi_ipa_common_sources = files([
+    'ipa_base.cpp',
+])
+
+rpi_ipa_common_includes = [
+    include_directories('..'),
+]
+
+rpi_ipa_common_deps = [
+    libcamera_private,
+]
+
+rpi_ipa_common_lib = static_library('rpi_ipa_common', rpi_ipa_common_sources,
+                                    include_directories : rpi_ipa_common_includes,
+                                    dependencies : rpi_ipa_common_deps)